Determination of metoclopramide in human plasma by LC-ESI-MS and its application to bioequivalance studies.

An LC-MS method for the determination of metoclopramide in human plasma was developed and validated. Sample preparation involved extraction with ethyl acetate. Chromatographic separation was performed on a Thermo Hypersil-Hypurity C18 (150 mm x 2.

Effects of Ginkgo biloba extracts on diazepam metabolism: a pharmacokinetic study in healthy Chinese male subjects.

Aim: It has been reported that Ginkgo biloba extract (GBE) is an inducer or inhibitor of microsomal cytochrome P450 (CYP) 2C19, and diazepam is a substrate of CYP2C19. Thus, it could be expected that GBE may alter the metabolism of diazepam.

Methods: The pharmacokinetic parameters of diazepam and one of its metabolites, N-demethyldiazepam, were compared after oral administration of diazepam (10 mg) in the absence or presence of oral GBE (120 mg bid, for 28 days) in 12 healthy volunteers.

Quantitative determination of pimozide in human plasma by liquid chromatography-mass spectrometry and its application in a bioequivalence study.

A simple, sensitive and specific LC-ESI/MS method was developed for the determination of pimozide in human plasma. Pimozide and cinnarizine (internal standard) were isolated from plasma samples by liquid-liquid extraction. The chromatographic separation was accomplished on a Thermo Hypersil-HyPURITY C18 reversed-phase column (150mmx2.

Quantification of prochlorperazine maleate in human plasma by liquid chromatography-mass spectrometry: Application to a bioequivalence study.

A sensitive and specific method using a one-step liquid-liquid extraction with dichloromethane followed by liquid chromatographic-electrospray ionization-mass spectrometric was developed and validated to determine prochlorperazine maleate in human plasma using amitriptyline hydrochloride as an internal standard. The samples were separated using a Thermo Hypersil-Hypurity C18 reversed-phase column (150mmx2.1mm i.

Role of anandamide transporter in regulating calcitonin gene-related peptide production and blood pressure in hypertension.

Objectives: To explore the role of anandamide (AEA) transporter in regulating calcitonin gene-related peptide (CGRP) production and blood pressure.

Methods And Results: Plasma levels of AEA, CGRP, asymmetric dimethylarginine (ADMA) and nitric oxide in patients with essential hypertension, spontaneously hypertensive rats (SHRs) and 2 kidney 1 clip hypertensive rats and the CGRP mRNA expression in dorsal root ganglion of rats were measured. Peripheral blood lymphocytes were isolated to examine the AEA transporter activity, the role of AEA transporter in regulating CGRP mRNA expression or the effect of exogenous ADMA on AEA transporter activity.

Development and validation of LC-MS method for the determination of lisinopril in human plasma and its application in a bioequivalence study.

A rapid, simple, and specific liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method has been developed and validated for the determination of lisinopril in human plasma. Enalaprilat was used as the internal standard (IS). Sample preparation of the serum involved deproteination with methanol twice, repeatedly.

Determination of mianserin in human plasma by high performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI/MS): application to a bioequivalence study in Chinese volunteers.

This study aims to develop a standard protocol for the bioequivalence study of mianserin hydrochloride tablets--a tetracyclic antidepressant drug. For this purpose, a rapid, convenient and selective method using high performance liquid chromatography coupled with electrospray ionization mass spectrometry (HPLC-ESI/MS) has been developed and validated to determine mianserin in human plasma. Mianserin and the internal standard (I.

Fingerprint of Hedyotis diffusa Willd. by HPLC-MS.

A HPLC-MS fingerprint method has been developed based on the consistent chromatographic features of the major chemical constituents among 10 batches of Hedyotis diffusa Willd. Chromatographic separation was conducted on a Hypersil-Keystone Hypurity C(18) column using methanol:water:acetic acid as the mobile phase. Major compounds, including oleanolic acid, ursolic acid and ferulic acid, were analysed by HPLC-MS.

Quantitative determination of erythromycylamine in human plasma by liquid chromatography-mass spectrometry and its application in a bioequivalence study of dirithromycin.

A sensitive, rapid liquid chromatographic-electrospray ionization mass spectrometric method for determination of erythromycylamine in human plasma was developed and validated. Erythromycylamine in plasma (0.2 mL) was extracted with ethyl acetate, the organic phase was transferred to another clear 1.

High-performance liquid chromatography with atmospheric pressure chemical ionization and electrospray ionization mass spectrometry for analysis of Angelica sinensis.

An HPLC-PAD-API/MS method for analysing the chemical constituents of Angelica sinensis (A. sinensis) has been developed. ESI and APCI spectra, in both positive ion (PI) and negative ion (NI) modes, provided very useful information concerning the molecular weights of detected compounds.

Determination of duloxetine in human plasma via LC/MS and subsequent application to a pharmacokinetic study in healthy Chinese volunteers.

Background: The pharmacokinetics of duloxetine hydrochloride have been well studied after its approval for clinical use. However, few such data have been reported in the English language literature. We developed a method to determine the pharmacokinetics of duloxetine enteric-coated capsules in healthy Chinese volunteers.

Quantitative determination of amantadine in human plasma by liquid chromatography-mass spectrometry and the application in a bioequivalence study.

A sensitive liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method is developed and validated for rapid determination of amantadine in human plasma. Desloratadine was used as the internal standard (I.S.

Level of asymmetric dimethylarginine and carotid atherosclerosis in patients with chronic kidney disease.

Objective: To determine the association between asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthase, with atherosclerosis in patients with chronic kidney disease (CKD).

Methods: One hundred thirty-eight CKD patients were enrolled in this study. Serum levels of L-arginine, ADMA, and SDMA were measured by high-performance liquid chromatography (HPLC).

Quantitative determination of azithromycin in human plasma by liquid chromatography-mass spectrometry and its application in a bioequivalence study.

A sensitive, rapid liquid chromatographic-electrospray ionization mass spectrometric method for determination of azithromycin in human plasma was developed and validated. Azithromycin in plasma (0.2mL) was extracted with methyl tert-butyl ether-hexane (50:50, v/v), organic phase was transferred to another clear 1.

Identification and determination of nucleosides in Cordyceps sinensis and its substitutes by high performance liquid chromatography with mass spectrometric detection.

Cordyceps sinensis (Cs) is a well-known traditional Chinese medicine (TCM) and Cordyceps mycelia (Cm), a cultured Cordyceps, is a substitute for Cordyceps sinensis. The most important active components in them are nucleosides. A high selective, sensitive and accurate high performance liquid chromatography method with photodiode array detection (DAD) and mass spectrometric detection has been developed for simultaneous separation, identification and quantification of nucleosides in Cs and Cm using a mobile phase including (A) ammonium acetate (40 mM, pH 5.

LC-DAD-APCI-MS-based screening and analysis of the absorption and metabolite components in plasma from a rabbit administered an oral solution of danggui.

A valid chromatographic fingerprint method using liquid chromatography-diode array detection-atmospheric pressure chemical ionization mass spectrometry in negative mode (LC-DAD-APCI-MS) is proposed for studying the absorption and metabolites of a traditional Chinese medicine (TCM) Angelica sinensis (danggui) in rabbit plasma, after the rabbit is administered with danggui oral solution (DOS). More than thirty-two common components were detected in both DOS and rabbit plasma, which shows that the components in the DOS were absorbed into the body of the rabbit. Of these, senkyunolide I, senkyunolide H, Z-6,7-epoxyligustilide, 3-butylidene-7-hydroxyphthalide, Z-ligustilide, Z-butylidenephthalide, Diels-Alder dimers of ligustilide, linolenic acid, linoleic acid and falcarindiol were tentatively identified from their MS, UV spectra and retention behavior by comparing the results with the published literature.

[Two-dimensional gel electrophoresis of matrix metalloproteinases in subretinal fluids].

In this work, the experimental conditions for two-dimensional gel electrophoresis of subretinal fluids (SRF) matrix metalloproteinases were established. The conditions tested included the composition of lysis solution and lysis method, the composition of rehydration solution and isoelectric focusing program (IEF), the composition of equilibration buffer and equilibration process and the composition of incubation solution and incubation methods. The main equipments used were IPGphor isoelectric focusing system from Amersham pharmacia and PROTEAN II xi cell from Bio-Rad, the gel strips used were the 18 cm long, pH 3 - 8 Linear immobiline DryStrips.

[Changes of serum asymmetric dimethylarginine in essential hypertension before and after the treatment].

Objective: To investigate the relationship between serum asymmetric dimethylarginine (ADMA) and blood pressure as well as target organ damage in essential hypertension, and to evaluate the effects of enalapril and losartan on them.

Methods: Forty-two newly diagnoszed patients with essential hypertension were randomly divided into enalapril-treated group and losartan-treated group. Serum ADMA, L-arginine, and nitric oxide( NO) were measured before and after the treatment for 8 weeks.

[Determination of adenosine and cordycepin in Cordyceps sinensis and C. militarris with HPLC-ESI-MS].

Objective: HPLC-ESI-MS to establish a method for simultaneous determination of adenosine and cordycepin in Cordyceps sinensis and C. militarris.

Method: HPLC-ESI-MS method.

[Relationship between serum asymmetric dimethylarginine and blood pressure in patients with chronic renal failure].

Objective: To investigate the relationship between serum assymmetric dimethylarginine and blood pressure in patients with chronic renal failure.

Methods: We examined the levels of asymmetric dimethylarginine (ADMA) in the serum and urine of 29 hemodialysis patients using the HPLC method, and assessed the relationship between serum ADMA and blood pressure.

Results: The level of serum ADMA was higher, but the level of urinary ADMA was lower in the patients with chronic renal failure than those in the controls.